GM Says Problem Occurred In Pre-Production of Saturn Ion

General Motors Co. said late Wednesday it knew of faulty ignition switches dating back as early as 2001—three years earlier than previously reported—and has yet to determine the full scope of the problem.

Separately, the maker of the component at the heart of a 1.6 million-vehicle recall said it only costs a few dollars to produce and minutes to install, which may provoke questions from investigators about why the problem wasn't fixed years ago. Auto-parts maker Delphi Automotive PLC told Wall Street analysts this week it...